I also want to know that

Since Soul Reap is treated as bonus damage then it won't play nice with the passive, similar to the interactions we see with Warmaster. (I'm 99% on this, will double check.)

I know rotos doesn't grant extra turn on kill for sure.

Pretty sure the soulreap gets the kill not inithwe, as I resurrected against him recently 

Would you still say that Soul Reap is the best blessing for Inithwe, despite the part about not making the kill non-revive?

Yes. The blessing only activates, if the enemy survives the initial hit and has a certain percentage of hp left. In this situation, you have no block revive with Soul Reap, but the enemy is at least dead - or no block revive without Soul Reap, because the enemy is still alive.

If Inithwe kills the enemy directly, block revive should activate as normal.